Due to its characteristics of being easily applicable to various products and electrical characteristics such as a high energy density, a secondary battery is not only commonly applied to a portable device, but universally applied to an electric vehicle (EV), a hybrid vehicle (HV), or an energy storage system that is propelled by an electric motor. This secondary battery is gaining attention for its primary advantage of remarkably reducing the use of fossil fuels and not generating by-products from the use of energy, making it a new eco-friendly and energy efficient source of energy.
A battery pack for use in electric vehicles has a structure comprising a plurality of cell assemblies connected in series, each cell assembly including a plurality of unit cells, to obtain high power. Also, the unit cell includes a cathode current collector and an anode current collector, a separator, an active material, and an electrolyte solution, and allows repeated charging and discharging by electrochemical reactions between the components.
In addition to this basic structure, the battery pack further includes a battery management system (BMS) to monitor and control a state of a secondary battery by applying an algorithm for control of power supply to a driving load such as a motor, measurement of electrical characteristic values such as current or voltage, charge/discharge control, voltage equalization control, state of charge (SOC) estimation, and the like.
Recently, with the increasing need for a high-capacity structure as well as utilization as an energy storage source, the demand for a battery pack of a multi-module structure in which a plurality of battery modules including a plurality of batteries connected in series and/or in parallel are assembled, is also increasing.
Because the battery pack of the multi-module structure includes a plurality of batteries, there is a limitation in controlling the charge/discharge state of all the batteries using a single BMS. Accordingly, a recent technology has been introduced in which a BMS is provided to each battery module included in the battery pack, one of the BMSs is designated as a master BMS, and the remaining BMSs are designated as slave BMS, such that the charge and discharge of each battery module is controlled in a master-slave mode.
In the master-slave mode, the master BMS communicates with the slave BMSs to collect various charge and discharge monitoring data associated with the battery modules for which the slave BMSs are responsible, or to transmit a control command to the corresponding slave BMS to control the charging/discharging operations of each battery module, so as to integratedly manage the charge and discharge of the battery modules included in the battery pack.
To collect data or transmit a control command through a communication network, the master BMS needs to pre-allocate an identification (ID) to each slave BMS to uniquely identify each slave BMS.
Existing methods are used by which a master BMS reads ID information pre-stored in a hardware circuit of a slave BMS, or a master BMS assigns an ID for each slave BMS by a program algorithm and transmits the IDs to each slave BMS. However, this traditional method has a disadvantage of requiring a separate hardware circuit for storing an ID.
As another related art, Korean Patent Laid-Open Publication No. 10-2013-0058373 discloses a method which wakes up multiple BMSs connected in series in a sequential order via a communication network and allocates IDs in a wake-up order. This related art has a drawback that a time required to allocate IDs increases with the increasing number of BMSs connected in series.
Accordingly, studies are actively being made on a system and method for allocating IDs to many BMSs quickly in a simple manner.